The invention relates to a support for supporting a substrate in a chamber and related methods of use and manufacture.
In the manufacture of integrated circuits, a substrate is processed by a plasma of process gas in a chamber. The substrate is typically supported in the chamber by a support, a portion of which may comprise a dielectric material covering an electrode. The electrode may be charged to electrostatically hold the substrate, to energize the process gas in the chamber, or to do both. In addition, the support may comprise a heater to heat the substrate, or a heat exchanger, such as for example, channels through which heat transfer fluid may be circulated to heat or cool the substrate. A heat transfer gas, such as helium, may also be introduced below the substrate to enhance heat transfer rates to and from the substrate.
The substrate fabrication process may be performed at elevated temperatures and using erosive gases. Temperatures exceeding 100xc2x0 C. in combination with gases such as halogen gasesxe2x80x94may result in rapid thermally degradation of the support. The erosion and temperature resistance may be met by polymer or ceramic materials, such as for example, polyimide, aluminum oxide and aluminum nitride. However, it is difficult to attach such polymer or ceramic supports to the chamber which is typically made from a metal. For example, differences in thermal expansion coefficient between the support and the chamber, or differences in temperature across the thickness of the support, may cause thermal expansion stresses that result in cracking or fracturing of either structure or at their joints and interfaces.
Another problem that often occurs with conventional supports arises because the heat transfer gas passed through the conduit in the support may leak out from the joints in the conduit, especially at the interfaces between different sections. A loss in pressure of the heat transfer gas during processing may cause non-uniform heat transfer rates, and consequently non-uniform temperatures, across the substrate. It is desirable to maintain uniform heat transfer rates from, and temperatures across, the substrate during its processing otherwise the substrate may be processed unevenly.
Therefore, it is desirable to have a support that may be used at elevated temperatures without uncontrolled thermal expansion or adverse thermal stresses. It is further desirable to maintain uniform heat transfer rates and temperatures across a substrate during its processing. It is also desirable to be pass heat transfer gas through conduits in the support without excessive leakage of the gas from joints and interfaces.
The present invention satisfies these needs. In one aspect, the present invention comprises a substrate support capable of holding a substrate in a chamber, the substrate support comprising at least one support section having a slot extending through the thickness of the support section, the slot being shaped and sized to reduce adverse thermal expansion effects during use of the support in the chamber.
In another aspect, the invention comprises a substrate support comprising an electrode, a dielectric at least partially covering the electrode, and a base below the electrode, the base comprising a thermal expansion slot.
In yet another aspect, the invention comprises a substrate processing chamber including a substrate support comprising an electrode that is at least partially covered by a dielectric and an underlying base comprising a slot, a gas distributor, a gas energizer, and a gas exhaust, whereby a substrate received on the support may be processed by gas introduced through the gas distributor, energized by the gas energizer and exhausted by the gas exhaust.
In a further aspect, the invention comprises a method of fabricating a substrate support comprising the steps of forming an electrode, covering the electrode at least partially with a dielectric, forming a base to support the electrode, and forming a thermal expansion slot in the base.
In a further aspect, the invention comprises a support capable of holding a substrate in a chamber, the support comprising a plurality of support sections that are joined to one another by at least one bond comprising a plurality of layers.